Light-curable compounds, such as adhesives and bonding or filling compounds, are widely used to attach objects to surfaces or to fill gaps or other openings, such as a cavity, in a tooth. Such curable compounds are generally available in a semi-solid state, and are manipulated and positioned on the surface or in the gap as desired, and hardened or cured into a more solid state for permanency. Curing or hardening is generally a chemical polymerization process which is promoted and driven by various curing conditions and factors. For example, a semi-solid compound or component thereof, may be cured by exposure to air or to energy, such as heat or light energy.
Today, many adhesive and filling compounds are cured by exposure to light energy, particularly visible light energy. The light curing process involves directing a beam of light, such as visible light, at a specific wavelength or band of wavelengths onto a semi-solid light-curable compound to cure the compound. The compound includes light sensitive, chemical components therein which, when exposed to light at the specific wavelength, generally polymerize to harden the compound onto the work surface to bond, fill, or coat the surface.
Specifically, light-curable compounds are widely used in dental procedures. Dentists use light-curable compounds for tooth repairs in a variety of applications including a base, a liner, a coating, a surface seal, a filling for caries and cavities, and to secure crowns or similar dental structures to a tooth surface. Generally, visible light in the blue range of the light spectrum will be sufficient to cure most commonly used dental compounds. Once cured, the dental compound functions, for example, to reduce further tooth decay, to bond dental structures, and/or to provide additional structural support to a tooth.
Generally, curing is effected by various instruments or devices capable of generating visible light, particularly a beam of blue light, and directing this light onto a tooth surface containing the light-curable compound. The blue light penetrates into the compound layer on the tooth surface for complete curing. The duration of the exposure to blue light for proper curing of the compound layer depends upon the light-curable compound itself, thickness of the compound layer, and the power and characteristics of the blue light emitted from the curing light instrument. For example, curing a compound to provide a thin tooth surface coating or veneer will require less light energy, while curing a compound to provide a thicker, deeper filling for gaps, such as caries and cavities, will require a greater amount of light energy.
Presently, the prior art dental curing light devices utilized to deliver blue light to the tooth have exhibited various drawbacks. For example, the blue light directed towards the tooth inevitably exposes the surrounding oral tissue to certain wavelengths of blue light known to be undesirable for human tissue. Hence, curing light devices must be tuned to emit light at the proper wavelength to cure a specific wavelength sensitive light-curable compound for proper curing and have their output radiation limited to within a suitable wavelength band.
Filtering of unwanted wavelengths of light is accomplished by use of complex filtering devices or special filters which receive broad spectrum light from a lamp element, such as a halogen lamp bulb, and allow only the light at the desired blue wavelength to pass through or reflect onto the light-curable compound. The undesired wavelengths are then deflected back into the housing of the instrument adding to the accumulation of heat during operation of the instrument. The heat must be dissipated and therefore, large heat sinks, fans and other devices are necessary. Furthermore, the heat degrades the operation of the bulb and shortens its effective life. In addition, filtering mechanisms often cause a loss of a portion or spectrum of radiation emitted by the light source. Only the specific angle of incidence of light entering the filtering device will be reflected to the curable compound while light outside the specific angle of incidence will be filtered out and lost.
While filtering and angle of incidence effect to decrease light intensity, the light intensity is further diminished by dispersion and scattering of light emitted from the light source. Curing light instruments of the prior art, particularly those utilizing filters, typically have a gap or an empty, hollow space between the light emission source and the filter or other means to direct or transmit the curing light out of the instrument and onto a light-curable compound. However, a portion of the light emitted into this space misses the outlet, thereby reducing the amount of light contacting the light-curable compound.
Thus, curing light instruments of the prior art, with or without filtering devices, are inefficient by virtue of loss of emitted light available to cure the compound. As a result, these instruments require more power output from the light source, increased light emission, and/or longer curing time. Consequently, such instruments also require larger and more efficient heat dissipation components which increases their overall cost and size. The size, cost of manufacture and operation, and decrease in convenience, to both the operator and the patient, renders these instruments less useful and less desirable.
Thus, there is a need to provide a curing light instrument to cure compounds in a fast, efficient, and effective manner, while improving convenience and reducing size and overall costs.
Accordingly, it is desirable to provide a curing light instrument which efficiently and effectively cures light-curable compounds by maximizing the amount of light directed onto the light-curable compound.
It is also desirable to provide a curing light instrument which is small, portable and convenient to use for curing light-curable compounds.
It is further desirable to provide a curing light instrument requiring low maintenance and radiating light from energy efficient light emitting elements having a long life.